This invention relates, in general, to semiconductor lasers, including, but not limited to, vertical cavity surface emitting lasers (VCSELs) having a sensing capability.
In the past, silicon sensors utilized a dynamic element, such as a deformable membrane or cantilevered beam that is displaced by pressure or an applied force. The detection of this displacement is done by measuring the change in piezoresistance or capacitance. One disadvantage of these silicon sensors is that the change in resistance or capacitance is very small and difficult to detect.
Another disadvantage of these silicon sensors is that they are typically large, thus increasing the cost per device. Cost is an important factor because in most applications, such as automotive or medical applications, a multiple amount of devices are used in each application to provide redundancy.